1. Field of the Invention
The invention relates to the field of tools for installing a vehicle tire on a wheel rim, and in particular to a manual pry tool for pushing both beads of a truck tire over one side of the rim.
2. Prior Art
Manual pry tools for installing a tire on a wheel rim are known. Such tools are operable to install a tire on a wheel rim having a lower rim flange disposed horizontally on a ground surface. Such tools generally comprise an elongated pry bar which has a handle end to be gripped by a user, and a flattened tool end for insertion between one bead of the tire, which is disposed horizontally above the wheel rim, and an upper wheel rim flange. The beads of the tire normally reside between the upper and lower flanges and the beads must be moved axially inward downwardly over the upper rim flange to install the tire on the rim. After the tool end is inserted between the tire and the wheel rim, the user applies pressure to the handle end, using the tool as a lever with the upper rim flange as a fulcrum, in order to pry a short length of the tire bead (which is of slightly smaller circumference than the wheel rim but can be resiliently stretched) over the upper flange of the wheel rim. The process is repeated in successive stages around the periphery of the wheel rim until a substantial circumference of the tire bead is passed over the rim, where upon the resilience of the bead assists in drawing the remainder of the bead to the inside of the rim between the rim flanges. Alternatively, after a length of the tire bead has been pried over the rim flange, a machine may be utilized for sliding the tool end circumferentially around the periphery of the wheel rim flange whereby the tire bead is pulled over the rim flange in a continuous motion. In either case, installing a tire on a wheel rim with the known installation devices is a difficult task. Further, many modern wheels are made from aluminum or have a polished metal surface to provide an attractive appearance. Such wheels are susceptible to damage when a tire is installed using the known installation tools. Further, the user often resorts to using a hammer to beat a portion of the tire bead over the wheel rim flange, and the wheel rim may be accidentally struck, causing nicks, cracks, bent rims, etc. There is a need for a tire installation tool which permits the installation of both the lower and the upper tire beads on the wheel rim in a simple operation, in a manner that allows single lever motions to pull the first and second beads over the rim flange in sequence, without requiring excessive force which may tempt a user to strike the tire bead with a hammer.